The invention relates to a process of preparing a high power explosive from a powerful explosive compound like cyclotetramethylenetetranitramine or cyclotrimethylenetrinitramine.
The invention also relates to a plastic bound high power explosive including at least 90 percent by weight of a powerful explosive like cyclotetramethylenetetranitramine or cyclotrimethylenetrinitramine and a maximum of 10 percent by weight of a stabilizing and binding agent comprising an organic polymer and additives.
Furthermore, the invention relates to a method for shaping the high power explosive by die-comprising the same. According to a known process of the initially mentioned kind, see U.S. Pat. No. 3,839,106 issued to Felix Louis Joseph Dubois de Prisque et al. on Oct. 1, 1974, a high power explosive is obtained by dispersing a powerful explosive compound like octogen (trivial name of cyclotetramethylenetetranitramine which will be used throughout the following) in a rubber-like two-component binder comprising a prepolymer having two preferably terminal carboxyl groups and an epoxide based crosslinking agent. Further a stabilizer like wax is added as well as other additives like catalysts for crosslinking the stabilizing and binding agent, antioxidants and surfactants. In detail, at first the binder components are mixed using a kneader at increased temperatures under vacuum; then the stabilizing and binding agent is blended with the octogen under the same conditions. Thereby a castable mass is obtained which is cast under the action of vibrations in molds wherein the mass hardens within a couple of days. Thus high power explosive shaped bodies are formed without the application of pressure and may contain up to 90 percent octagon by weight of the total.
A similar process (French Patent Office Publication No. 2.225.979) employs a two-component binder comprising di-isocyanates and polyols; however, in the high power explosive shaped bodies thus obtained the proportional amounts of octogen are below 90 percent by weight of the total.
The known process is somewhat involved in that the stabilizing and binding agent as such and the octogen are required to be blended in a kneader under vacuum at increased temperatures and in that the subsequent casting process will have to be conducted under vacuum, too. Throughout thereof vibrations must be applied to achieve the desired homogeneity. Additionally, the entire process becomes time consuming due to a hardening period of several days. The high power explosive shaped body finally obtained thereby still contains 10 percent by weight or more of foreign matter so that its explosive strength is considerably decreased as compared to that of pure octogen.
It is known to combine hexogen (cyclotrimethylenetrinitramine) and poly tetrafluoroethylene in aqueous dispersion; the warm-dried combination product comprises 97 percent hexogen and 3 percent poly tetrafluoroethylene by weight of the total and becomes plastically deformed already under low pressures, see German Auslegeschrift 1,571,227 issued to Imperial Chemical Industries Ltd. of London, U.K. The effect of the poly tetrafluoroethylene is said to result from the low friction between the explosive particles coated therewith. However, due to the low friction between the particles of the explosive, the bodies shaped therefrom do not have sufficient dimensional stability.
It is further known from German Offenlegungsschrift 14 46 875 issued to Dynamit Nobel AG that graphite or talc may be used as a lubricant for pentaerythritol tetranitrate in proportional amounts of 0.3 to 5 percent, the mixture being prepared in aqueous dispersion. To eliminate the formation of electrostatic charges on for example octogen use of special carbon blacks is recommended which have a specific resistance of below 1 Ohm cm and a specific surface area above 20 m.sup.2 per g and which may be applied to the surface of the explosive particles in proportional amounts of up to 0.5 percent.